The long term objectives of this study are to investigate the factors responsible for the progressive layering of cells during development of the chick neural retina. Our working hypothesis is that cells possess and respond to unique cell surface characteristics which determine the position of cells within the tissue. In previous work, we have developed procedures that allow us to isolate specific cell populations from the 14 day embryonic neural retina. These cell populations possess distinct morphology and associative behavior. The immediate objectives of this project are to isolate and characterize factors which promote the adhesion of specific retinal cell types. The information obtained from this study will contribute to our understanding of the development of the complex neural structure of the retina, and, by extension, the central nervous system.